Tool for grinding, polishing, boring and milling for dental and medical purposes



TOOL FOR GRINDING, POLISHING. BORING AND MILLING FOR DENTAL AND MEDICALPURPOSES Filed Nov. 15, 1954 p ,1958 E. HOFFMEISTER 2,851,777

INVE/ViO/P I. .H'ofiaz e atcr United States TOOL FOR GRINDING,POLISHING, BORING AND lgggllgNG FOR DENTAL AND MEDICAL PUR- Thisinvention relates to an instrument for grinding, polishing, drilling andmilling, more particularly for dental and medical purposes, comprising ahand piece with a rotatable driving shaft therein, and a tool unitcomprising a tool arbor rotatable in a long guiding hearing which isinserted in a tubular extension of a front bearing for said drivingshaft provided within the hand piece, the said tool arbor having a toolthereon in proximity to the forward end of the long guiding bearing anda drive element in proximity to the rear end of the long guiding bearingfor co-operation with a drive element on the forward end of the drivingshaft. For the purpose of securing the tool unit in position on the handpiece, the said tubular extension is provided with a radial aperturewithin which a ball is radially displaceable to enable it to enter agroove located in the long guiding bearing to receive the ball, alocking device being provided for forcing the ball inwardly to engagethe groove in the long bearing member of the tool unit and to maintainit in engagement with the groove.

The present invention has for its object to provide an improved lockingdevice which can be operated by means of an actuating member located onthe outside of the hand piece in the neighbourhood of the part which isnormally gripped during the use of the instrument and which is therebyin a position where it can be conveniently operated and is not in theway when operating the instrument.

The accompanying drawings show one constructional form of the inventionby way of example.

In these drawings:

Figure 1 represents a hand piece with the tool inserted in longitudinalsection, the ball being in the locking position;

Figure 2 represents the tool unit having a long guiding bearing with anannular groove, also in longitudinal section; a

Figure 3 shows the front bearing for the driving shaft with theextension thereof which serves to receive the tool unit, also inlongitudinal section;

Figure 4 shows the bearing according to Figure 3 in plan.

Referring to Figs. 1 and 2, the tool arbor 1 is rotatable in a longguiding bearing 2 and is combined therewith to form a tool unit whichcan be inserted into the front end of a hand piece 3 provided with adriving shaft 8. The tool arbor 1 is held in position in the bearing 2by means of a collar 32 at its front end and by means of a collar 33 atits rear end, a tool 31 being provided on the arbor 1 in proximity tothe forward end of the bearing 2. The tool arbor 1 has a drive elementthereon in proximity to the rear end of the bearing 2, the said drivingelement being in the form of a slotted extension 34 of the collar 33 andco-operating with a drive element 35 on the forward end of the drivingshaft 8.

A forward bearing 7 for the driving shaft 8, also shown separately inFig. 3, is arranged within the hand piece 3 which comprises a removablepoint 18 having an axial 2,851,777 Patented Sept. 16, 1958 ice openingtherein to receive the front end of an integral tubular extension 9 ofthe bearing 7, the wall of the said axial opening having a screw-threadtherein and the tubular extension 9 has a screw-threaded portion 21 tofit said screw-thread. After removal of the point 18 from thehand-piece, the bearing 7 with its extension can be screwed into thepoint 18 from the inside. For screwing the bearing '7 into position, theextension 9 is provided with a collar 19 having radial slots 16 thereinfor engagement by driving members provided on a tubular spanner.

The tubular extension 9 of the bearing 7 receives the long guidingbearing 2 of the tool unit and has a radial aperture 17 therein withinwhich a locking ball 5 is located, the said aperture tapering towardsthe inside of the tubular extension to prevent the ball 5 from fallingout when the bearing 2 of the tool unit is removed. The guiding bearing2 of the tool unit is provided with a circumferential groove 4 which isadapted to register with the radial aperture 17 when the bearing 2 isinserted in the tubular extension 9.

The bearing 7 and its tubular extension 9 is surrounded by a sleeve 6,the inner wall of which has a conically divergent forward end 61 forco-operation with the ball 5. The sleeve 6 is displaceable axially onthe bearing 7 and its extension 9 from a position in which the ball 5can enter the wider portion of the said conically divergent end of theinner wall of the sleeve 6 and leave the groove 4 in the bearing 2, intoa position in which the narrower portion of the inner wall of the sleevebears against the ball, forcing it into the groove 4. The sleeve 6extends rearwardly lengthwise of the hand piece and is slidable on atubular guide member 10 surrounding the driving shaft 8 and extendinginto the sleeve 6. The rear end of the guide member ltl fits over a rearbearing 13 of the shaft 8 and is provided with an integral flange 11which abuts against a retaining member 12 for the bearing 13, which isformed as a rocker bearing.

The sleeve 6 is urged into its locking position by means of a helicalspring 14 which encircles the guide member 10, the said flange 11forming the rear abutment of said spring, while the other end of thespring bears against a flange 2t) integral with the rear end of thesleeve 6. By means of the spring 14 the sleeve 6 is moved forwardly, theconically divergent end 61 of the inner wall of the sleeve sliding overthe ball 5 and forcing the ball inwardly to engage the groove 4 in thebearing 2, thereby securing the tool unit in position.

In order to enable the tool unit to be exchanged, it is necessary todisplace the sleeve 6 rearwardly, and for this purpose the sleeve isprovided with a shoulder 24 in proximity to its rear end and adjoiningthe flange 20. The shoulder 24 is engaged by a stud 25 integral with aslide member 15 which is displaceable lengthwise on the outside of thepart 26 of the hand piece enclosing the rear end of the sleeve 6, andwhich is normally gripped by the hand during the use of the instrument,the stud 25 extending through an axial slot 27 in the part 26 of thehand piece. In the operative position of the sleeve 6 shown in Fig. l,the stud 25 is located in the forward end of the slot 27 but bydisplacing the member 15 rearwardly by finger pressure the stud 25 ismoved towards the rear end of the slot 27 and retracts the sleeve 6against the force of the spring 14, allowing the ball 5 to leave thegroove 4 in the bearing 2 and thereby freeing the tool unit to enable itto be removed.

I claim:

1. An instrument for grinding, polishing, drilling and milling, moreparticularly for dental and medical purposes, comprising in combination,a hand piece having a 0 rotatable driving shaft therein, a drive elementon the forward end of said shaft, a forward bearing for said drivingshaft within the hand piece with an integral tubular extension having aradial aperture therein, a tool unit comprising a long guiding bearingfitted into said tubular extension, a tool arbor rotatable in saidguiding bearing and having a tool thereon and a drive element engagingthe drive element on the driving shaft, located in proximity to theforward and rear ends of the guiding bearing, respectively, said guidingbearing having a groove therein to register with the aperture in thetubular extension, a ball in said aperture, a sleeve surrounding saidtubular extension, the inner wall thereof having a conically divergentforward end for co-operation with said ball, and means including anactuating member on the outside of the hand piece for axially displacingthe sleeve from a position in which the ball can enter the wider portionof the conically divergent end of the inner wall of the sleeve and leavethe groove in the long bearing member of the tool unit, into a positionin which the narrower portion of the inner wall of the sleeve bearsagainst the ball to force it into the said groove and secure the toolunit in position.

2. An instrument for griding, polishing, drilling and milling, moreparticularly for dental and medical purposes, comprising in combination,a hand piece having a rotatable driving shaft therein, a drive elementon the forward end of said shaft, a forward bearing and a rear bearingfor said driving shaft within the hand piece, said forward bearinghaving an integral tubular extension with a radial aperture therein, atool unit comprising a long guiding bearing fitted into said tubularextension, a tool arbor rotatable in said guiding bearing and having atool thereon and a drive element engaging the drive element on thedriving shaft, located in proximity to the forward and rear ends of theguiding bearing, respectively, said guiding bearing having a groovetherein to register with the aperture in the tubular extension, a ballin said aperture, a tubular guide member within the hand piecesurrounding the driving shaft in proximity to said rear bearing thereof,a sleeve slidable at its front end on said tubular extension and at itsrear end on said tubular guide member, the inner wall of said sleevehaving a conically divergent forward end for co-operation with saidball, and means including an actuating member on the outside of the handpiece for axially displacing the sleeve from a position in which theball can enter the wider portion of the conically divergent end of theinner Wall of the sleeve and leave the groove in the long bearing memberof the tool unit, into a position in which the narrower portion of theinner wall of the sleeve bears against the ball to force it into thesaid groove and secure the tool unit in position.

3. An instrument for griding, polishing, drilling and milling, moreparticularly for dental and medical purposes, comprising in combination,a hand piece having a rotatable driving shaft therein, a drive elementon the forward end of said shaft, a forward bearing for said drivingshaft within the hand piece with an integral tubular forward extensionhaving a radial aperture therein, a tool unit comprising a long guidingbearing fitted into said tubular extension a tool arbor rotatable insaid guiding bearing and having a tool thereon and a drive elementengaging the drive element on the driving shaft, located in proximity tothe forward and rear ends of the guiding bearing, respectively, saidguiding bearing having a groove therein to register with the saidaperture in the tubular extension, a ball in said aperture, a sleevesurrounding said forward bearing, tubular extension and driving shaft,the inner wall of said sleeve having a conically divergent forward endfor co-operation with said ball, a spring arranged within the hand pieceand bearing against the rear end of said sleeve to urge the sleeveforwardly to force said ball into the narrower portion of the inner wallof the sleeve and into said groove in the long guiding bearing of thetool unit to secure the tool unit in position, and means including anactuating member on the outside of the hand piece for axially displacingthe sleeve against the force of said spring into a position in whichsaid ball can enter the wider portion of said conically divergent endand leave the groove in the long guiding bearing of the tool unit torelease the tool unit.

4. An instrument as claimed in claim 3, having a rear bearing for thedriving shaft with a retaining member therefor Within the hand piece, atubular guide member Within the hand piece surrounding the driving shaftand extending into said sleeve for slidably supporting the rear endthereof, and a rear abutment for said spring comprising a. flangeintegral with the rear end of said tubular guide member and abuttingagainst said retaining member for the rear bearing of the driving shaft.

5. An instrument for grinding, polishing, drilling and milling, moreparticularly for dental and medical purposes, comprising in combination,a hand piece having a rotatable driving shaft therein, a drive elementon the forward end of said shaft, a forward bearing for said drivingshaft within the hand piece with an integral tubular forward extensionhaving a radial aperture therein, a tool unit comprising a long guidingbearing fitted into said tubular extension, a tool arbor rotatable insaid guiding bearing and having a tool thereon and a drive elementengaging the drive element on the driving shaft, located in proximity tothe forward and rear ends of the guiding bearing, respectively, saidguiding bearing having a groove therein to register with the saidaperture in the tubular extension, a ball in said aperture, a sleevesurrounding said forward bearing, tubular extension and driving shaftand having a shoulder thereon in proximity to its rear end, the innerwall of said sleeve having a conically divergent forward end forco-operation with said ball, a helical spring within the hand pieceencircling said driving shaft and bearing against the rear end of saidsleeve to urge the sleeve forwardly and force the said ball into thenarrower portion of the inner wall of the sleeve and into said groove inthe long guiding bearing of the tool unit to secure the tool unit inposition, the hand piece having an axial slot therein in the partthereof which encloses the rear end of the sleeve, and a slide memberdisplaceable lengthwise on the outside of said part of the hand pieceand having a stud thereon extending through said slot and engaging saidshoulder to displace the sleeve against the force of said spring into aposition in which said ball can enter the wider portion of saidconically divergent end and leave the groove in the long guiding bearingof the tool unit to release the tool unit.

6. In instrument as claimed in claim 3, in which the hand piececomprises a removable point having an axial opening therein to receivethe front end of said tubular extension of the forward bearing of saiddriving shaft, the wall of said axial opening having a screw threadtherein and said tubular extension having a screw threaded portionengaging said screw thread so as to enable the bearing and tubularextension to be screwed into the point from the inside, said extensionhaving an integral collar with radial slots therein for engagement by aspanner for screwing the bearing into position.

Homann Mar. 31, 1903 Bergstrom July 23, 1935

